The invention relates to an electromagnetic relay.
In such a known electromagnetic relay (British Patent 2,072,949), the switching contact of the relay, arranged on a hinged armature, operates in conjunction with a fixed normally-open contact which must be set to a predetermined contact pressure when the relay is switched on and to a particular contact spacing when the relay is switched off. For this purpose, the contact carrier of the normally open contact has an area which is bent away at a right angle next to the normally-open contact, and is provided with at least one notch for stretching this area of the contact carrier in the known electromagnetic relay. Dependent on the number and depth of the notches, the normally-open contact is selectively moved towards the switching contact of the hinged armature until the required relay data such as erosion reserve, contact pressure and contact spacing are achieved.
However, the disadvantageous factor in this solution is that due to the notching process, the normally-open contact is not always accurately raised with parallel faces to the switching contact of the hinged armature. Instead, the normally-open contact can also be slightly tilted sideways or towards the rear due to a non-uniformly hard structure in the material of the contact carrier, which can then lead to an unwanted unilateral resting of the switching contact against the normally-open contact and leads to more rapid contact erosion. During the notching of the contact carrier, considerable tool forces also become effective over its entire width which must be absorbed by a stable support at the rear of the contact carrier in order to avoid damaging the relay. The space required for this, however, exists only in the case of power relays with relatively large dimensions so that the known solution cannot be implemented either because of lack of space in the production of relatively small relays. In this connection, the application of several notches for a required stretching of the contact carrier is particularly expensive, since several operating cycles are required for each notching process, such as setting notching level, measuring, applying stamp dye, stamping, retracting stamp dye.
The present solution attempts to carry out the stretching of the contact carrier for setting up the relay contact even in narrow space conditions in such a symmetrical manner that tilting away of the relay contact to the side or to the rear is avoided during this process.